1. Field Of The Invention
The present invention relates generally to downhole tools, and more particularly to a hydraulic timer for providing a time delay in the operation of the downhole tool.
2. Description Of The Prior Art
The hydraulic timer of the present invention is particularly adapted to use in downhole tools such as fluid sampling devices which trap a sample of well fluid.
The fluid sampling devices of the prior art include various devices which have hydraulic time delays built into the operational mechanism of the tools so as to slow the travel of the operating mechanism. An example of such a device is shown in U.S. Pat. No. 4,903,765 to Zunkel, and assigned to the assignee of the present invention, which shows a recent improvement in such fluid sampling tools, wherein the fluid sampling tool is constructed to have a time delay which starts when a valve of the tool first starts to move in response to pressure from the well.